Bridge



2 Sheets-Sheet 1.

(No Model.) S. A. BUCHANAN.

BRIDGE.

Patented Sept. 25, 1888.

(No Model.)

2 Sheets-Sheet 2.

S.-A.QBUOHANA N.

BRIDGE.

Patented Sept. 25, 1888.

UNITE rams SAMUEL A. BUCHANAN, OF BELIJEFON'IAINE, OHIO.

BRIDGE.

SPECIFICATION forming part of Letters Patent No. 389,951, datedQeptember 25, 1888.

Application tiled September 10, 1887. Serial No. 249,872. (No model.)

To all whom it may concern:

Be it known that I, SAMUEL A. BUCHANAN, a citizen of the United States,and a resident of Bellefontaine, in the county of Logan and State ofOhio, have invented, new and useful Improvements in Bridges, of whichthe following is a specification.

My invention relates to improvements in wooden bridges and in theconstruction of the same.

Figure 1 is a perspective of one truss of my bridge; Fig. 2, a bottomview of a portion of the bridge; Fig. 3, an end View of the top chordand king plate; Fig. 4, a detached perspective of my iron packing-ring;Fig. 5, aperspective view of my king-plate. Fig. 6 is an elevation and aplan of my improved splice; Fig. 7, a perspective of my pin-socket; Fig.8, a bottom view of the sway braces in a three panel bridge.

A is the top chord of a bridge; 13, the bottom chord; O 0, end posts; DD D, suspensionloops; E, main diagonal; F,hip-casting; G,pinsocket; G,grooved casting; H, counter-tie; I, plate to which counter-tie isattached; L, nuts attached to the ends of the main diagonals and bearingon the hip-castings; M M, floor-beams; N N, sway-braces; O O,adjusting-blocks; P, adjusting bolts or screws; Q, plates to which theouter ends of the counter-ties are attached; R, king plate; S, shouldersthereon; T, inclined edge or water-shed; U, hole in the plate forpassage of the king-bolt Y; V V, nuts on the ends of thesuspension-loops; Qiron packing-ring; a, bolts that bind the parallelbraces together; I), the vertical bolts in the chordsplice; c, thehorizontal bolts in this splice.

The principal improvements in my inven tion are, first, making thesuspension-loops adjustable, so as to be able to true up and aid inkeeping the top chord in line and crossing them to give greaterbearings; second, the ready adjustment of the sway-braces; third, thehip castings on the ends of the upper chord and end posts, which supportthe main diagonals and suspension loops, and which may also form arain-hood for the end of the planks that cover the top chords and endposts; fourth, the use of my iron packing-rings in splicing and unitingthe timbers, doing away with the scarf-blocks and packingblocks;

fifth, my king-plate for uniting the end posts and bottom chords.

The construction of my bridge and the difference between it and otherbridges of this class are as follows: In the ordinary manner ofconstructing wooden bridges the main timbers are the end posts, top andbottom chords, and the struts that receive the strain from vertical rodsand convey the same diagonally from upper to lower panel-points, thestrain being delivered at the top of the end posts. In my construction Isuspend the load of intermediate floor-beams on the main diagonal rods Eand counters H, passing from the top of the top chord under thefloor-beams and carrying the weight to the upper chord and end posts.This plan covers any desired number of panels.

Instead of the usual style of mortising the end of the bottom chord forthe foot of the end post to rest in, I form mortises in the bottom ofthe post and top of the bottom chord, in which I insert an ironking-plate, It, having either tenons or ribs that fit in the mortises inthepost and chord,and bolt thepost and bottom chord together by aking-bolt passing through the king-plate and binding on iron bearingsabove the post and beneath the chord. This king-plate has an inclinedflange at each bearin g-edgeof the post and chord-timbers designed toturn the rain from the edges and prevent its entrance between thetimbers and kingplate. The object of myking-plate is to form a moredurable connection between the chord and end post by protecting the sameas far as possible from injury by the weather and doing away with thepocket for collecting rain, that is always made Where the end of the endpost is mortised into the bottom chord.

One great trouble with wooden bridges is that the wood in seasoning, orfrom the effects of the weather, becomes warped, causing the upper chordto buckle or go out of line, thus weakening the bridge. To obviatethisIsuspend my floor-beams from the top chord by means ofthe crossedsuspension-loops D,which have the nuts V V on theirlower ends. Now,should the top chord be thrown out of line by warping, settling, orother cause, by loosening the nut V and tightening up the nut V, or viceversa, as desired, the top chord can be drawn into line again and heldin place by the loop. The loop may be made in two pieces when preferred,the upper ends being attached to a bolt passing through the upper chord.

My main diagonals may be made of one piece passing from the top of theupper chord under the floor-beam. The lower end ofthe countertie ispassed underneath the floor-beam and up to the top of the bottomehord,where it is attached to a plate, Q, recnforcing thesuspension-loop at that panel and keeping the floor-beam in position.

In making the splice in my lower chord the scarf-bloelgusually mortisedinto the spliced ends and filling the space between the timbers, is doneaway with, instead of which I insert my iron packingrings having largeoutside or end surfaces that abut against the sides of the timbers 13I5, but which are only large enough at their middle to allow the passageof the bolts that unite the timbers and sustain the pressure. This shapeof the packing-rings causes them to turn all rain falling on them awayfrom the timbers and gives a larger bearing'surface with the use of asmall amount of metal. Bolts are inserted through the timbers, throughthe packing-rings, and through the splice-plates, binding all firmlytogether. Other bolts are inserted through the timbers vertically,bearing against the sides of the horizontal bolts. These vertical boltsare to prevent splitting of the timbers and to prevent the horizontalbolts shearing through the timbers by excess of tensile strain of bottomchord.

Instead of the usual mode of fitting and bolting the sway-braces inposition underneath the bridge rigidly, I fit them in place and pass abolt through the floor-beams between the ends of the braces. On one orboth ends'of this bolt, as necessary, I fit a wedge-shaped block, 0,that is beveled to fit between the swaybraces. Under the old plan, asthe bridgetimbers seasoned or settled, the braces soon ceased to fit inposition, failed to do their work properly, and were liable to splitwhere nailed or bolted on. As soon as my braces become loose from theseasoning of timber, the shrinkage can be taken up by a turn of the nutson the bolt 1, forcing the blocks 0 up and spreading the braces untilthey come to a taut bearing.

My manner of adjusting the sway-braces when used in a three-panel bridgeis as follows: In the end panels the braces are arranged in the mannershown in Fig. 2. The outside ends are separated the width of the bridge,or as far as desired, while the inside ends are brought together againstthe floor-beams. Between the floor-beams in the center panel I place twoparallel braces, held apart by my packingrings at each end, throughwhich rings the bolts (6 pass, that bind the pieces together. Mywedge-blocks are placed between the swaybraces in the end panels in theusual way and adjusted by the screwbolt, except that the ends of thesebolts in the middle panel have hooks or eyes on them that fit around thepacking-rings on the bolts a, holding the two parallel braces together.The tightening up of the wedge-blocks draws the floor-beams and parallelbraces taut together at the same time that it takes up any looseness ofthe swaybraees in the end panels, tightening up the whole systemuniformly.

In construction I employ a middle post at I alongside of thesuspension-loop, between the top and bottom chords, but have left it outof the drawings to prevent confusion, as I have only sought to show theconstruction of the main diagonal, counter-tie, suspension-loops, topand bottom chords, and end posts.

What I claim is 1. The chords A B, posts G, main diagonal E, passingunder and supporting the doorbeam M, and counter-tie II, passing underthe floor-beam and sustained by the chord, as and for the purpose setforth.

2. The chord A, floor-beams M, and the onepiece adjustable crossedsuspension-loop D, passing over and around the chord and suspending thefloor-bcam, as and for the purpose set forth.

3. The king-plate It, the lugs, and the water-sheds or flanges Z, as andfor the purpose set forth.

4. The sway-braces N, one on d resting freely in the corner where thechord and cross-beams or joists meet, or in a pocket provided for it,the other end resting freely against the side of the cross beams orjoists, the bolt 1 and wedge-blocks O, that hold the separated ends ofthe braces against the cross-beams or joists, all combined substantiallyas shown and described.

5. The bottom chord-splice, composed of the timbers B B, ironpacking-rings NV, and bolts 1) c, as and for the purpose set forth.

6. The combination of the parallel braces with the packingrings IV, asand for the purpose set forth.

7. The combination,with doublefloor-beams, braces, posts, chords, orother parts of a blit ge, of the packing-rings IV, as and for thepurpose set forth.

SAMUEL A. BUCHANAN.

Witnesses:

J. A. nt-invit L. E. Pn'r'rrr.

